"Andrew Burgess" wrote in message
...
It is an indoor pump, so I place it inside an upside down
flower pot (hole sealed up). I also place a small nightlight
inside the flower pot so that condensation doesn't get sent
down the tubing and then plug it up by freezing. (zone 5 here)

Hmmm. That might make it more likely to freeze, no? The bulb heats
the air under the pot and since it's probably on damp soil more
moisture enters the warm air. Then this warm damp air is sent into a
cold air line and the temperature drops and the water condenses out.

Well for my situation, during the first winter the tubing froze a
couple times before adding the nightlight and never since (two
more winters).

Like I mentioned in another post, I live in Colorado which has
very dry air, especially in the winter. That might have something
to do with it. Also, the ground under the pot appears to be very
dry, which might be partly because the nightlight has dried it out.

Jerry